The present invention relates to the recognition of handwritten characters, and in particular a process and a system for recognizing handwritten characters on documents of the type of forms to be filled in.
Modern techniques involving computers nowadays permit the automatic reading of handwritten documents under conditions in which the cost is very much greater than the cost of a manual operation.
However, automatic processing of handwritten documents is possible with high efficiency only if documents of the form type are used which have been pre-printed by first filling in boxes which are to be read.
Pre-printing requires the user, or writer, who fills in a document of the form type, to properly position the characters and to write legibly a character in each box. In each of these cases, the writer is asked to write a letter (generally a capital letter), a number or an X.
The written document is then read by an electro-optical detector which generally delivers a signal which can have two levels, a first level corresponding to the shade of the handwritten characters, and a second level corresponding to the color of the paper in the boxes. An image processing means then carries out a recognition of the handwritten characters located in the boxes and causes to correspond to each box a binary series of data according to known techniques.
During processing, it is obviously necessary to separate or eliminate the characters previously printed on the document. Several processes have been used to carry out this elimination, and in particular the use of non-actinic printing. This process however has drawbacks, in particular the requirement of printing the material in at least two colors.
Another process not having these drawbacks is described in French patent application 95 10031. The process described in this patent application consists in using a form containing printed boxes in which are to be handwritten characters adapted to be read by an optical recognition device, the boxes being predefined by predetermined motives constituting elements characterized by at least one parameter verifying a predetermined relationship so as to be able easily to eliminate, during reading of the document, the objects as to which the parameters verify the predetermined relationship as being constituent elements of the predetermined designs.
Although effective, this process requires however that the form comprise on its face or below the boxes to be filled in the nature of the information to be to be written in these boxes, such as xe2x80x9cNAMExe2x80x9d, xe2x80x9cGIVEN NAMExe2x80x9d, xe2x80x9cADDRESSxe2x80x9d, etc. This printing, which is necessary so that the correct information will be written by the writer in the appropriate boxes, obviously has the principal drawback of occupying a substantial surface of the form and hence wasting paper.
This is why the principal object of the invention is to provide a system of handwritten character recognition using a form in which no surface is used to write in information relative to the boxes to be filled.
The principal object of the invention is thus a process for handwritten character recognition in a document of the form type containing printed boxes as well as pre-inscribed characters within the boxes in which corresponding characters are to be handwritten according to the indications supplied by the pre-printed characters, the printed boxes and the pre-printed characters being constituted by predetermined elements characterized by at least one parameter verifying a predetermined relationship whilst the predetermined relationship is not verified for the handwritten characters. The process comprises the steps of reading the document by successive elemental zones with the help of a character recognition device, determining that the parameter or parameters characterizing a read object in a set of elemental zones verifies the predetermined relationship, and eliminating the objects for which the predetermined relationship is verified as being predetermined elements.
Another object of the invention is the provision of a document of the form type containing printed boxes in which to handwrite characters adapted to be read by an optical recognition device, the boxes containing pre-printed characters supplying indications to the user to write therein handwritten characters as well as printed boxes that the pre-printed characters are constituted of predetermined elements, characterized by at least one parameter verifying a predetermined relationship whilst the predetermined relationship is not verified for the handwritten characters, so as to be able easily to eliminate, during reading of the document by an optical recognition device, the objects whose parameter or parameters verify the predetermined relationship as being predetermined elements.